<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS 引入方式</title>
  <!-- link 引入外部样式表； rel：关系，样式表 -->
   <link rel="stylesheet" href="./my.css">
</head>
<body>
  <p>css引入方式</p>
</body>
</html>